Enhanced visible light photocatalytic degradation of rhodamine B by Z-scheme CuWO4/g-C3N4 heterojunction

The g-C3N4-based heterojunction photocatalysts have aroused worldwide attention for improving photogenerated charge carrier’s lifetime and photocatalytic activity. In this study, a series of CuWO4/g-C3N4 composites were prepared by a simple hydrothermal method, and then its structural characteristics were analyzed using XRD, SEM, FT-IR, UV–vis DRS, XPS, and N2 adsorption–desorption techniques. The photocatalytical activities of CuWO4/g-C3N4 composites were clearly evaluated by the photodegradation experiments of rhodamine B (RhB). The obtained results shown that CuWO4/g-C3N4 composite with the mass ratio of 10% CuWO4 displayed the highest degradation efficiency (93%) for RhB within 150 min in the photodegradation processes, which corresponded well with the pseudo-first-order kinetics. Obviously, the construction of Z-scheme CuWO4/g-C3N4 heterojunction can effectively improve photocatalytical efficiency, which is owing to fast separation of electron–hole pairs and enhancement of redox ability. Besides, the photodegradation efficiency can still keep more than 80% after four cycles, and then the reaction mechanism of photocatalysis was fully discussed to prove the formation of Z-scheme system. This work provides a certain theoretical foundation for the designation and research of g-C3N4-based Z-scheme heterojunction photocatalyst.